As the demand for high capacity and low power consumption memory devices has increased, research into next-generation memory devices such as non-volatile memory devices that do not require a refresh operation has been actively conducted. These next-generation memory devices should have a high integrity characteristic like that of a Dynamic Random Access Memory (DRAM), have a non-volatile characteristic like that of a flash memory, and have high speed like that of a static RAM (SRAM). Phase-change RAM (PRAM), Nano Floating Gate Memory (NFGM), Polymer RAM (PoRAM), Magnetic RAM (MRAM), Ferroelectric RAM (FeRAM), and Resistive RAM (RRAM) have been highlighted as some of the next-generation memory devices, for example.